Taking Over
by suddenlyperry
Summary: Silly mortals, falling for my every more. Taking over Isabella and her life is not a problem at all. And the best part is, there is nothing she can do to get herself back. Until when the demon clock strikes 12:00 on Halloween night, I have taken over. *Phineas and Ferb Fanfiction-Halloween-Special! Enjoy!*
1. Chapter One- So Colourful

**Present Day: October 28th 2013**

Isabella's Prospective-

I really love candy, and costumes, and parties... I just over all love Halloween! The one day of they year where you can dress up as someone else. In some ways, I guess you can say not being yourself and being someone you look up to can boost your self confidence. But it's only one day anyway.

This Halloween is looking like the best Halloween yet! Phineas and Ferb are planning a Halloween Party!Knowing those boys, they will go full out. Plus, the day after Phineas and Ferb's party is the Halloween Dance! I'm so excited!

My friends helped me pick the best costumes! One for the party and one for the dance. They are so cute.

I am a big time waster, Tumblr is so addicting is kind of bad. Also, I think I may have gained like five pounds. My mom brought me a "little Halloween treat" which was a bowl of candy. And I may have stuffed my mouth with it. But hey, its candy I mean come on.

Either way, this week looks great. Nothing bad could possibly happen. This should be perfect.

* * *

**Meanwhile, In the Demon Dimension...**

Gisabella's Prospective-

The Rising, that's what today is. And I am so excited, I love causing trouble. The Rising is a huge deal in my dimension, and it takes a lot of explaining for some people to understand what the rising is. On the week of Halloween, our leaders choose numerous demons to be sent to the dimension's of their counterpart mortal, where we corrupt them for the week, until when the demon clock strikes 12 and we are all sent back to our dimension.

Out of all the dimensions, the demon dimension is the largest. We are a underworld, but the demon dimension if the underworld of the living things. The bad parts of them that is. Then, there is the underworld of the died. But I'm not going to get into that. The Demon Dimension is made out of numerous planets, representing the living dimensions and their worlds. We are the same people as our living counterpart, we all live the same ways, we aren't how the living humans think ghost and demons are. The only difference is that we are the demons of our counterparts and we have the rising. Not too much, but if you haven't realized I'll tell you, the demon dimension is very complicated*.

So, as you can imagine. Being picked to join the rising is such a big deal, and I'm in it this year!

I have two counterparts, one in the first dimension and one in the second. Both named Isabella, but both very different. I am being sent to the first dimension this year, and I plan on doing a great job this year, so I will get chosen again.

"Gisabella!" My mother called from upstairs, "You better get going to the gates, it's almost time for the Rising. Good luck Gisa!"

"Thanks mom!" I hollered up to my mom, I leaped off the couch and raced out the door.

I didn't stop running until I reached the gates. For each of the worlds in the demon dimension, there are gates. Year round they are locked, until the Rising that is.

Only five people that I didn't know had flew in from different places in my world to be transported to the first dimension, so we will never meet.

The leaders would send all the demons, but if we where all there, it would be the same as this dimension. Expect for the fact that all the other dimensions are very colourful. Also, if we where all there we would have no silly mortals to mess with.

I waited for several minutes, trying to contain my excitement and before I knew what was happening the huge gates opened with a big clang, a cool breeze swept through us. We where turning into spirits. We flew through the gates and the cool breeze grew stronger, and I saw we where heading to a bright light. A couple seconds later, I found I was alone, still heading to the light. It was so bright I shut my eyes. When I opened them I was...

* * *

**In the First Dimension...**

Gisabella's Prospective-

I opened my eyes, I was in the first dimension. Wow, its really colourful.

When you get transported through the gates, you do turn into a sprit. Until you find your counterpart that is.

I was in a bright purple room, sitting on a matching purple bed was a girl with long, dark hair and she looked just like me.

_That must be Isabella. _I thought to myself.

I flew into the body, for a bit, I lost control of what I was doing. But when I opened my eyes I was in the body of Isabella. The real Isabella is being pulled back into my dimensions containment unit, and she wont remember anything from what happened. But all of her friends, family, and... well everyone else will remember.

I got up and walked over to the light purple mirror in Isabella's room. I looked the same as she would normally, but my eyes where jet black, and every so often they glistened dark, deep red. Like blood.

Before being sent to this dimension I did research on Isabella, so I know everything about her and everything about her friends and family. So no one will know the difference. I stood up and walked over to her closet, it was full of dresses and bows. Finally, after looking through her closet for many minutes, I found and outfit that I would wear. It was a jet black dress with a cropped dark red jean jacket. I paired it with high dark boots and black-stud earrings. _Perfect._

I walked into her bathroom and pulled out her make-up bag. I applied dark eye liner and mascara. And dabbed my lips with some lip balm. I want my look to be Halloween-believable, like I still am Isabella. Ill just say this is my "Halloween Look"

I laughed in spite of myself.

This week is going to be awesome. I will dominate.


	2. Chapter Two- Pumpkins

Gisabella's Prospective-

I stepped out of my house and a cool breeze greeted me, I walked across the street to where Isabella's friends Phineas and Ferb lived. It was time to start messing with things.

I swung their gate open, "Hey Ferb, Whatcha doing?" I said with a devious glint in my eyes.

From my statement, both boys looked generally surprised. Phineas's eyes grew wide, and him and Ferb exchanged glances.

"Um... We where just planning the Halloween party" Ferb said, and from that _I _was surprised. I thought Ferb didn't talk much.

I walked over and sat in fount of the two brothers.

"Nice... look Isabella" Phineas spoke up, studying my new appearance.

"Thanks. It's my Halloween look" I said.

"So what are you doing today?" I asked, trying to act like the Isabella Phineas and Ferb know so they don't suspect anything. After all, their profiles said they where geniuses.

"We where thinking of making a machine that creates jack-o-lanterns. You know, for our party. So we have a lot" Phineas said, "What do you think?"

"Really?" I grunted "It's more fun making you own jack-o-lanterns."

"Okay, but" Phineas began,

"You guys could make a super growth formula and pour it on some pumpkin seeds, and you will have your instant pumpkins, I'll carve them and you guys can continue getting your party ready."

"It will be a lot of pumpkins." Phineas began, but I cut him off again.

"Flynn, I am going to carve the pumpkins." I said, and leaned towards him, staring into his eyes flirtatiously. "Unless you don't trust me with little ol' pumpkins. Flynn, I thought you trusted me."

His eyes grew wide as he meet my gaze, he started to mumble and sputter, "It's just a lot of pumpkins to carve by yourself..."

I turned to Ferb, giving him the same stare as I did to Phineas. "I bet Ferb trusts me with the pumpkins" I turned back to Phineas, giving him a glare. "They are just stupid pumpkins, and I can carve them. I am a fireside girl."

"Ok, ok" He said, still slightly shuddering. "Ferb and I will get started on the growth formula."

I watched as they walked away to get the things they needed, I sat there smugly. I am just starting my plan to mess with Isabella's life. When I was going through Phineas's profile it says that he as a little crush on Isabella. And he is very oblivious. Isabella must be sucking at the whole flirting thing, because by the end of the day, I'm going to have Phinny wrapped around my finger. Then I will work on the rest of Isabella life. Messing up everything about it. Tomorrow is Tuesday, which means school. Perfect.

Phineas and Ferb walked back into the backyard with a container full of bubbling green fluid and a little packet of pumpkin seeds. Before my eyes they opened the pumpkin seed packet and poured the fluid into the bag. They threw the bag into the air, and it erupted, sending pumpkin seed flying in all directions over their backyard. Seconds later, pumpkins sprouted from the ground.

"You know Isabella, Ferb can work on the Halloween party. I'll help you with the pumpkins." Phineas mumbled, looking at me in the eyes.

"Well, maybe Ferb wants to crave the pumpkins Flynn. Let Ferb talk for himself." I said sharply, turning to Ferb. "Well Ferb?" I said, smiling at him.

"Um, I do like to carve pumpkins" Ferb said.

I turned to Phineas, ready to make a smart remark but he was glaring at Ferb. Which made a smug smile glide across my face. I have him wrapped around my finger sooner than I thought. I turned back to Ferb,

"You know what I like decorating better" Ferb said, and walked away into the house.

"I'll go get the knives" Phineas said,

"I don't need a play by play" I mumbled below my breath.

Phineas turned around, "Did you say something Isabella?"

"No, I want a sharp knife please." I told him, In return, he raised an eyebrow. But he left to get the knifes anyway.

I looked around the backyard and picked the biggest pumpkin to start out on. Phineas came back with knifes and sure enough, mine was pretty sharp. I took the knife from him and began carving at the pumpkin. So far I'm not really causing too much trouble. Like I would like too. But what I am going to do sure is going to cause some confusion between the two brothers. Even though I am in Isabella's body, I can just my black magic. I will use a spell on this pumpkin. That might make a certain two get in a fight. I finished my carving, I looked to make sure Phineas wasn't watching and casted my spell. The pumpkin grew whole again. I carved another symbol on the pumpkin, and used the same spell again. Then I carved yet another sign on the pumpkin. What I was casting was a seeing spell. Phineas will see one thing on the pumpkin, Ferb will see another, and all the other people will see something totally different. I just can't wait to see Phineas's reaction to this pumpkin, also Ferbs.

I pushed my finished pumpkin away and pulled at another one close to me. I began carving the pumpkin, cutting out normal Halloween symbols and faces. I continued to make spiders, creepy faces, black cats, witches and more on the pumpkins. Finally, Phineas spoke up.

"So Isabella, you have been acting differently today." He said, yet he was still focused on his pumpkin he was carving. "Is something wrong?"

I laughed, got up and walked towards him, sitting right next to him.

"Oh Phineas, I know I have been acting different. But maybe you like it. Me spending all this time with you? But I feel like I have been taken over by a... demon or something, but maybe it's just the sprit of Halloween calling me. I am so excited for this week."

"Yah, I'm excited too and-"

"I think you really like me huh..." I whispered in his ear, "So tell me Phinny, will there be seven minutes of heaven at you party? Because if there is I am coming early, because that what you want isn't it? To be alone with me? That's why you wanted to carve the pumpkins with me"

He was still looking down at his pumpkin, but his carving had stalled.

He opened his mouth, about to speck but the buzz of my phone cut him off. And he looked relived.

I took a quick glance at my phone, my mom wanted me home for dinner.

I looked up at Phineas, trying to look as flirty as I could, "Oh, I got to go. But I know something real good we could do with seven minutes" I whispered to him, "I'll give you a sneak peck, because I know that's what you want."

I leaned over to him, and kissed him on the cheek. He still was focused on his stupid pumpkin.

"Well bye, Flynn" I called out, walking out of his backyard. I had left him stunned, helpless, with all the pumpkins to carve. I had him wrapped around my finger just like that. Like I had planned.


	3. Chapter Three- Over you

Gisabella's Prospective-

I opened my eyes, I was greeted by Isabella's bright purple room. To be honest, it stung my eyes.

Today is Tuesday, Halloween is two days away! Only two days. I have to start my master plan today. Also, the Halloween dance is tonight. Phineas and Ferbs party is tomorrow, and Halloween the day after. My seclude is packed. I have to start messing with Isabella's life today if I want to impress the leaders and get chosen for the rising next year. So in other words, today is a big stepping stone for my future of being chosen for the rising.

I hopped out of bed, whipping my head to the side and taking a quick glance at myself in Isabella's mirror. Wow, her hair is crazy puffy in the morning. I was tempted to laugh at the was Isabella's hair looked, but until 12:00 Halloween night, I technically am Isabella. I walked over to her closet, pushing aside all of the purple dresses and bows. At the back of her closet, (where I had found my outfit I had wore yesterday) I found a long sleeved ruby sweater, a pair of denim jeans, a black belt and a pair of black boots. I also found a red bow, the same colour as the sweater. I settled for this look today. The bow pulled together the whole "Isabella look" so I think I can pull this off and everyone will believe I am Isabella.

I got changed, and walked out of Isabella's closet and into her bathroom. I brushed my teeth and did my hair in long black curls. I also pulled out Isabella's makeup bag and applied some mascara, eyeliner and some light red lip gloss. I pulled Isabella's backpack onto my shoulders, and grabbed her phone in my hand.

Like I said before, when I was in my dimension I did some research on "miss perfect" also known as Isabella. I know all the classes she has, what she is learning, and I also have her cell password. Its all too easy. I ran down the stairs and to the front door. I pulled the black boots on and reached for the door handle.

"Isabella? What are you doing?" A voice sounded.

It was Isabella's mother.

"You haven't eaten any breakfast"

"Oh, sorry mom. Not hungry. See you after school" I called out to Isabella's mom as I opened the front door.

"Ok, bye sweetheart!" She called to me, but I was already running down the street to the bus stop.

I forgot that in this dimension people atruly care where I am going and what I'm doing. My parents wouldn't care less if I disappeared and didn't come back for days.

I reached the bus stop, and my eyes landed on Phineas and Ferb, they where standing with Buford, Balijeet, Django and the fireside girls.

"Hey Isabella" Buford called out to me, "Phineas told me that you where all over him yesterday. Carving pumpkins? Ring a bell?"

Oh he thinks he is so smart. I'm almost tempted to laugh.

I walked up to Buford, "Well yah Buford. But I guess he didn't tell you that he totally wanted me to."

Buford's eyes grew wide, his already huge smile was growing bigger. "Wow dinner-bell, you didn't tell me about that."

Phineas's face was growing as red as his hair. "I never said I wanted you too" He said quietly.

Everyone looked back at me now, expecting me to burst into tears or whatever Isabella would do. But I'm Gisabella, not Isabella.

"Don't listen to him you guys, he wanted me to. You know Phineas, he sucks at this stuff." I said smugly.

"Well, she does have a point." Adyson spoke up, "Phineas does suck at romance."

I guess Fireside girls always have each others backs, because from beside Adyson, the rest of the fireside girls nodded in unison.

Phineas's face was on fire now. "I don't suck at romance. And I didn't ask her too"

Buford was holding back his laughter, and to be honest, so was I.

"Hear that Isabella? Phineas said he didn't want you to. Your crush of what? Eleven years doesn't like you."

Now everyone looked at me worriedly, like from that "blow" I was going to pass out, or cry.

"Well, ok. If Phineas doesn't want all of this," I said, gesturing to my body and face. "Then so be it, I know of so many other guys that do like me."

Everyone's jaws dropped. Phineas's eyes grew wide, then soft. And then, a little hurt. _He wants me, or um, Isabella. I knew it all along, that's why I'm messing with his feelings. Time to backstab, big time._

"She did not just say that" Django whispered to Balijeet, who eyes where large with shock.

"Well? What did you guys think? I was going to wait forever?" I retorted, was my counterpart really so weak for this guy?

Buford nodded, so, I slapped him. I turned to Phineas who was looking at his feet.

"If you want me I suggest you make a move now Phineas."

He stammered, but in the end, he just looked at his feet.

"Ok, the search for a boyfriend is on." I declared, to my still shocked audience.

It was perfect timing, the bus pulled up and I hopped on. Phineas, Ferb, Buford, Balijeet, Django and the fireside girls fallowing after me.

I searched through the seats, from my research, I knew just who to use. I walked to the back and sat down beside a guy named Conner. He was a bad-boy. He had been arrested twice. He cheats, lies, steals, he's perfect.

He looked up at me when I sat down next to him, raising an eyebrow. "What do you want?"

"Oh nothing Conner," I said, eyeing him. "But the real question is what do you want from me?"

"What do you mean?" He asked, giving me a glare.

"Please, I see the way you look at me. You like me" I whispered in his ear.

"I don't look at you at all" He retorted,

"Well than you're missing out." I said, smiling at him. "Because you could easily be mine."

He smirked, "You know what? I like the way you think Isabella. How about you, me. Tonight. The dance?"

I smiled, biting my lip. "How about this?" I asked, pulling Conner into me. Kissing him, and wow, he is a good kisser.

Once we broke apart, I murmured into his ear: "Sounds like a plan. Ill meet you at the dance. I'm going to be a devil. And do yourself a favour, get my number. If you don't have it, get it."

I looked up to here my "friends" sat, they where all looking at me. Jaws hung open. I smirked and mouthed "told you" to them. I glanced at Phineas, the poor kid looked like he was going to faint.


	4. Chapter Four-Better Than That

Phineas's Prospective-

What just happened. Did I miss something? Sure, I like Isabella. Heck, maybe I like her more than a friend. But there was no way I was going to let my friends know that. But now, how could Isabella turn away from me so quickly? Lately, I was staring to think Isabella liked me. More than a friend. But was I wrong?

Isabella hasn't necessarily been acting herself lately. Ok who am I kidding, she is like a totally different person! Polar opposite from the Isabella I'm used to. Its like she has an alternate personality, a.k.a whoever she is today. Her "Halloween look" isn't just affecting her looks. I guess her personality too.

What is happening? I don't get confused too often. But this is a problem I cant seem to solve. What happened to my best friend?

* * *

Gisabella's Prospective-

Ha-ha, Phineas is as white as a ghost. This is too perfect. I still have Phineas's wrapped around my finger, as long as Conner once I totally grab his trust. Which I admit, might be a difficulty. The bus pulled up to our school. We all stood up in unison, and filed off the bus. Once I stepped off the bus, I was surrounded by Isabella's friends. _So clingy. _

"Isabella! What was that?" Katie asked, her eyes where still opened wide with dis-belief.

"I told you, I'm over Phineas and now I'm going out with Conner. Its as simple as that." I said and smiled to the disbelieving crowd of people that now surrounded me.

"Isabella, Conner is bad news" Adyson called out.

"I don't care, he's nice to me. He likes the way he thinks" I said, smiling. I hate having to pretend to like this Conner guy, or anyone in this dimension. "Plus, he is a great kisser."

I shot a glance over to Phineas, who was standing next to Ferb. He was staring at his feet again. "How you must really like those shoes huh Phineas?" I murmured.

"Leave him alone Isabella." Django called from Phineas's side.

I smiled slyly, "Whatever you say Django, Ill leave Phinny alone. I just thought we where still friends. But I guess I was wrong. See you later guys" I said, walking away from the group and into the school.

* * *

Phineas's Prospective-

Today sucked, really sucked. I know I am not good with expressing my feelings but I really did like Isabella, and looking back on it, I'm surprised I didn't cry. Isabella ignored me the whole day, I guess we really aren't friends anymore, and that pretty much put me on mute for the entire day.

In my school, gossip spreads pretty fast. And where ever I would go people would give me looks. I didn't know why, but they did. And now, tonight is the dance, and tomorrow is my party. The day after is Halloween. I cant just not go to the dance, I've already bought my ticket. And I can't un-invite Isabella to my party, it's rude. And I don't do rude. I guess I'll spend the time at the dance and the party trying to get Isabella to talk to me. If she had time away from Conner. I hate that guy, he is bad news. He failed a grade to.

I was dressed in a vampire costume for the Halloween dance, Ferb- or should I say Ferbenstein, was Frankenstein. We jumped into my moms car. She still wasn't here yet, so Ferb spoke up. For once.

"Hey man are you ok?" He asked, looking concerned.

"Yah, I'm fine." I replied, playing it off the everything was fine. "Why wouldn't I be ok?"

"Well, Isabella was one of your bestfriends, and I even think you where starting to like her. She just turned on you and her huge cru- I mean huge friendship with you. I don't know why, but I would think you would take it harder than this."

I looked at my feet again, it was like my head was a weight, and it kept falling to my shoes. The whole day. "I guess a smile can hide so much huh."

He nodded, and gave me a smile. "Everything will be alright in the end bro. A lot of people will come in and out of your life."

I sighed, "Yah, I just thought Isabella wasn't one of those people."

"Just forget about Isabella for tonight, the dance isn't just for her and her new boyfriend. Its everyone's dance. You just need to go out and have a good time. Plus, all of our friends will be there. You just need to surround yourself with friends and positive people right now. Don't try to be the guy Isabella wants, be who you want to be"

"Wow Ferb, you're really good at this, you could be a guidance consular or something" I said and laughed, Ferb was right. Tonight, I'm going to be happy. "Thanks bro"

"No problem."


End file.
